Hydraulic turbine inlet configuration

ABSTRACT

An intake configuration for a low head hydraulic turbine installation wherein the inlet control gate is positioned upstream from the entrance to the turbine water passageway inlet and is located below the level of the turbine headwater reservoir. The upstream side of the gate body is constructed and arranged to combine with the turbine water passageway inlet to present an efficiently smooth contoured approach for the water into the turbine. When in the open position, the bottom gate seal coacts with the top of the inlet to insure that the water will follow the contoured surface of the upstream side of the gate body.

United States Patent [151 3,693,356 y Jr. et al. [451 Sept. 26, 1972 [54] HYDRAULIC TURBINE INLET 2,62l,483 12/1952 Kalix ..25l/30l CONFIGURATION FOREIGN PATENTS OR APPLICATIONS [72] Inventors: Howard A. Mayo, Jr.; Edwin W. 3 85 /l93 G tB t 6 /25 M hb th fY rea I'laln y a 422,453 .4/1967 Switzerland ..251/299 [73] Asslgneez Allis-Chalmer Manufacturing Com- 659,759 5/1938 Germany ..415/151 pany, Milwaukee, Wis.

Primary Examiner-l-Ienry F. Raduazo [22] 1970 Attorney-John P. Hines, Robert B. Benson and [21] Appl. N0.: 81,862 Arthur M. Streich 521 US. Cl ..6l/25, 415/147 [57] ABSTRACT [51] Int. Cl. ..E02b 7/40, FOlb 25/02 An intake configuration for a low head hydraulic tur- [58] Field of Search ..415/ 146, 147, 151; 251/298, bine installation wherein the inlet control gate is posi- 25 299 300; 1 19 25 2 tioned upstream from the entrance to the turbine water passageway inlet and is located below the level 5 References Cited of the turbine headwater reservoir. The upstream side of the gate body is constructed and arranged to com- UNITED STATES PATENTS bine with the turbine water passageway inlet to present an efficiently smooth contoured approach for 2 f g the water into the turbine. When in the open position, l7975 3 g the bottom gate seal coacts with the top of the inlet to 3 33 at a 1 insure that the water will follow the contoured surface 2888036 5/1959 zgii' j l of the upstream side of the gate body. 3,039,482 6/1962 Goldberg ..254/298 1 Claim, 7 Drawing Figures HYDRAULIC TURBINE INLET CONFIGURATION This invention pertains in general to a hydraulic turbine inlet configuration and more particularly to the combination of an inlet gate and inlet passageway which form the configuration.

It is recognized that hydraulic turbines provide one of the least expensive means of developing electric power because of the utilization of the force of water flowing from a higher elevation through the turbine to a lower elevation. As the needs for electrical power, both in the United States and throughout the world, have increased, the number of unused natural geographical locations with a sufficient water head to install'hydraulic turbines has decreased to the point where there are very few such locations remaining. Therefore, a different type of turbine has been developed for installation at low head sites. These turbines, such as that disclosed in US. Pat. No. 3,184,218, have been refined both from an engineering and cost standpoint to where it is now commercially feasible to utilize these low head sites to produce electrical power.

The turbines must be less expensive than the normal vertically disposed turbines and as efficient as possible to take full advantage of the low head. Of equal importance to the overall installation commercial feasibility is the cost and efficiency of the auxiliary equipment. Particularly, the water passageways for "free discharge spillways as wellas the turbine intakes and the necessary valving must not decrease the already low head to any greater degree than is absolutely necessary.

In order to reduce cost in a hydraulic turbine installation, it is desirable to provide the shortest possible intake to the turbine runner thereby decreasing the amount of concrete in the foundation. However, in order to maximize efficiency of the turbine, the water must have a minimum amount of turbulence as it enters the turbine runner. If the approach to the turbine inlet passageway through the inlet valve is not sufficiently streamlined, the passageway must be extended to overcome theturbulence in the water before it enters the runner. This adds to the cost of the hydraulic installation.

Sector or Tainter gates are relatively inexpensive to manufacture. They include a valve body having a configuration to block the flow of water through a passageway and usually two arms extending from the valve body and pivoted from a support. In most instances, the valve body is lifted from and lowered into blocking engagement with the water passageway by a hoistconnected to the valve body. In most known installations, the pivot connection for the valve arms has been downstream from the passageway inlet, and the valve body is lifted out of the stream of water when the valve is in the open position.

Extending the valve arms upstream permits streamlining the arms with a flat configuration since they are in tension and not subject to buckling forces. Since the arms and pivot transmit the hydraulic load on the gate to concrete piers, the concrete is, therefore, in compression with respect to the main structure downstream. Less concrete is therefore required since this is its strongest application.

Furthermore, by combining a sector gate of a particular shape with a turbine inlet passageway of a particular shape, the cost of the installation can 'be reduced, and the turbulence in the inlet passageway maintained at a minimum.

In this invention the valve. body upstream surface forms a streamlined approach to the turbine inlet which is the area of maximum velocity, therefore, reducing entrance head losses and permitting a less expensive short passageway to the turbine runner. Furthermore, the lower valve seal coacts with the upper inlet surface to insure water will not seep therebetween and cause turbulence when the valve is open.

It is therefore the general object and intention of this invention to provide an efficient, inexpensive hydraulic turbine inlet configuration which utilizes a sector gate to form part of the inlet water passageway.

Other objects of the invention will become more fully apparent as the following description is read in light of the attached drawing wherein:

FIG. 1 is a plan view of a hydraulic turbine inlet configuration constructed in accordance with the invention taken along the lines [-1 of FIG. 2;

FIG. 2 is a side elevation partially in section of the inlet configuration of FIG. 1 showing the gate in closed position and in phantom lines showing the gate in open position;

FIG. 3 is a cross section taken along the lines III-III of FIG. 2;

FIG. 4 is an enlarged view of the side seals;

FIG. 5 is an enlarged view of the bottom seal; and

FIG. 6 is an enlarged view of the top seal; and

FIG. 7 is an enlarged view of the bottom seal engaging the top seal.

Referring to the attached drawing, the hydraulic installation shown generally at 6 is conventionally a concrete installation providing a water reservoir or source generally designated 7. The hydraulic installation also defines a turbine water inlet passageway 8 which directs the water onto the turbine runner (not shown). The water inlet passageway 8 has top, bottom and side walls ll, 12 and 13, respectively. The-top wall 11 terminates at the inlet 9 and is positioned below the level of the water in the reservoir 7. The side walls 13 of the passageway 8 extend into the reservoir to pier noses 14 as best shown in FIG. 2. Trash rack bars 15, when required, are supported by the piers and lintle 10 at an inclination such that the flow has a minimum obstruction and debris is pushed to the top where it is more accessible and out of the main flow path.

The sector gate is composed of a gate body 16 and a pair of spaced arms 17 extending upstream therefrom. These arms are pivotally connected to mounting members 18 in any conventional manner to permit swinging movement of the gate between open and closed positions. As best shown in FIGS. 1 and 2, the arms 17 are positioned within the water reservoir 7 so that the arms do not obstruct the main stream of flow in the passageway 8. Furthermore, as best shown in FIG. 3 in the preferred embodiment of this sector gate, the arms 17 are streamlined as shown.

The downstream portion 19 of the sector gate body 16 may be completely open or provided with a cylindrical closure which is a radius from the pivot point of the arms 17 Seal elements 21 and 22 may be provided at the top and bottom of the gate body. These seals may be in the form of a flexible material such as neoprene.

The seals may be connected to the valve body in any conventional manner such as by bolting. In the closed position as shown in FIG. 1, each seal mates with a seal seat 23 and 24 provided in the top and bottom walls 1 l and 12 of the inlet 9. In the preferred embodiment, the lower seal element 22 on the valve body, as best shown in the enlarged view of FIG. 5, is in cross section a music note seal positioned for engagement with the upper seat 23 when the valve is in the open position shown in phantom lines in FIG. 2. The bottom seal 22 will block the flow of water between the valve body and the upper wall 11 of the inlet when the valve is open. With this preferred arrangement, water is only permitted to enter the passageway between the valve arms 17. No water is permitted to flow between the upper wall of the passageway and the valve body which would create turbulence in the flow. Side seal elements 25 are positioned for engagement with seats 26 which are flush with side walls 13 and present no obstruction to the flow passageway.

The upstream side 27 of the valve body 16 is streamlined to present an efficiently contoured surface to the flow of water when the valve is in the open position shown in phantom lines in FIG. 2. The lower upstream surface of the valve body is constructed to terminate in a line which is substantially tangent to the upper wall 11 of the passageway inlet 9 when the valve is in the open position. The valve in effect performs two functions: (i) a shutoff valve, and (ii) a streamlined extension of the inlet passageway 8.

Without this streamlined upstream surface of the valve body, a more costly streamlined approach would have to be included in the concrete foundation where the water enters the inlet 9. This would require another type of valve, possibly of the vertical lift type, at inlet 9 with gate slots in side walls 13 at the point of highest velocity, thereby causing extra head loss and cost. Without such a streamlined approach, less flow of water could be accommodated through the turbine.

Furthermore, unless there is a streamlined approach to the inlet 9, the passageway 8 would have to be lengthened so that turbulent water would not enter the turbine runner.

From the above description it can be seen that by utilizing a sector gate having a streamlined configuration as described above, the efficiency of the low head inlet configuration can be maintained. Since the sector gate itself provides the streamlined approach to the inlet of the passageway to the hydraulic turbine runner, the added expense of providing this streamlined approach in the installation has been overcome, and the goal of keeping the cost of this type of installation for use with low head sites atv a minimum has been achieved.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. An inlet configuration for a low head hydraulic turbine installation having a water reservoir comprising in combination: a turbine inlet passageway having top, bottom and side walls defining an inlet to said passageway, said inlet being located completely below the level of the water in said reservoir; seal seat means formed on said top and bottom walls; a gate valve body having a air of spaced seal elements positioned to engage sat seat means to block the flow of water from said reservoir into said inlet when in the closed position; means including radially disposed support arms connected to said gate body pivotally supported upstream from said gate body to permit swinging movement of said gate body in said reservoir on the arc of a circle between open and closed positions, said seat means and said seal elements being located on said arc defined by said valve body; and surface means on the upstream side of said gate body constructed and arranged to mate with the top wall of said passageway when the gate is open to provide a streamlined water approach from said reservoir into said inlet. 

1. An inlet configuration for a low head hydraulic turbine installation having a water reservoir comprising in combination: a turbine inlet passageway having top, bottom and side walls defining an inlet to said passageway, said inlet being located completely below the level of the water in said reservoir; seal seat means formed on said top and bottom walls; a gate valve body having a pair of spaced seal elements positioned to engage said seat means to block the flow of water from said reservoir into said inlet when in the closed position; means including radially disposed support arms connected to said gate body pivotally supported upstream from said gate body to permit swinging movement of said gate body in said reservoir on the arc of a circle between open and closed positions, said seat means and said seal elements being located on said arc defined by said valve body; and surface means on the upstream side of said gate body constructed and arranged to mate with the top wall of said passageway when the gate is open to provide a streamlined water approach from said reservoiR into said inlet. 